Write pole magnetic guard

Abstract

A data storage system may have at least one data writer that incorporates a write pole that continuously extends from an air bearing surface. The write pole can be separated from the air bearing surface by a side shield that consists of a first magnetic layer positioned on the air bearing surface and a guard layer separated from the air bearing surface by the first magnetic layer. The guard layer may be configured with a different magnetic saturation flux density than the first magnetic layer.

What is claimed is: 
     
       1. An apparatus comprising:
 a write pole continuously extending from an air bearing surface (ABS); and 
 a side shield separated from the write pole on the ABS and continuously extending from the ABS, the side shield comprising a magnetic layer, magnetic guard layer, and non-magnetic layer, the magnetic layer and magnetic guard layer being dissimilar materials, the magnetic layer continuously extending from the ABS to a first plane, the magnetic guard layer extending to a second plane and separated from the magnetic layer by the non-magnetic layer that surrounds the magnetic guard layer, each plane extending parallel to the ABS with the first plane being farther from the ABS than the second plane. 
 
     
     
       2. The apparatus of  claim 1 , wherein the magnetic layer and magnetic guard layers have dissimilar magnetic flux densities. 
     
     
       3. The apparatus of  claim 1 , wherein magnetic guard layer has a uniform thickness along the ABS, the thickness measured perpendicular to the ABS. 
     
     
       4. The apparatus of  claim 1 , wherein the non-magnetic layer continuously extends to opposite sides of the magnetic guard layer. 
     
     
       5. The apparatus of  claim 1 , wherein the magnetic guard layer and magnetic layer are each separated from the write pole by a common gap distance. 
     
     
       6. The apparatus of  claim 1 , wherein the magnetic guard layer and magnetic layer are separated from the write pole dissimilar gap distances, the magnetic guard layer being farther from the write pole than the magnetic layer. 
     
     
       7. The apparatus of  claim 1 , wherein the non-magnetic layer is separated from the ABS by the magnetic layer. 
     
     
       8. The apparatus of  claim 1 , wherein the magnetic guard layer has a varying thickness. 
     
     
       9. An apparatus comprising a write pole continuously extending from an air bearing surface (ABS) and separated from a side shield by a first distance on the ABS and by a second distance distal the ABS, the first distance being smaller than the second distance, the side shield continuously extending from the ABS and comprising a magnetic layer, magnetic guard layer, and non-magnetic layer, the magnetic layer contacting the ABS, the magnetic guard layer separated from the magnetic layer by the non-magnetic layer that surrounds the magnetic guard layer, a transition surface in the magnetic layer transitions from the first distance to the second distance, the transition surface separated from the ABS. 
     
     
       10. The apparatus of  claim 9 , wherein the transition surface is oriented parallel to the ABS. 
     
     
       11. The apparatus of  claim 9 , wherein the transition surface is separated from the magnetic guard layer by the non-magnetic layer. 
     
     
       12. The apparatus of  claim 9 , wherein the magnetic guard layer has a varying width along a length of the magnetic guard layer. 
     
     
       13. The apparatus of  claim 9 , wherein the magnetic layer continuously extends from the ABS along orthogonal first and second sides of the magnetic guard layer. 
     
     
       14. The apparatus of  claim 9 , wherein the magnetic layer is separated into front and rear sections by a notch, the notch partially extending through the magnetic layer. 
     
     
       15. An apparatus comprising:
 a write pole continuously extending from an air bearing surface (ABS); and 
 a side shield separated from the write pole by a first distance on the ABS and by a second distance distal the ABS, the first distance being smaller than the second distance, the side shield continuously extending from the ABS and comprising a magnetic layer, magnetic guard layer, first non-magnetic layer, and second non-magnetic layer, the magnetic layer contacting the ABS, the magnetic guard layer configured in an L shape and separated from the magnetic layer by the first non-magnetic layer, the magnetic guard layer continuously extends along orthogonal first and second sides of second non-magnetic layer, a transition surface in the magnetic layer transitions from the first distance to the second distance, the transition surface separated from the ABS. 
 
     
     
       16. The apparatus of  claim 15 , wherein the magnetic guard layer is surrounded by non-magnetic material. 
     
     
       17. The apparatus of  claim 15 , wherein the magnetic guard layer has a first thickness along a cross-track surface of the second non-magnetic layer and measured perpendicular to the ABS, the magnetic guard layer having a second thickness along a longitudinal surface of the second non-magnetic layer and measured parallel to the ABS, the first thickness being smaller than the second thickness. 
     
     
       18. The apparatus of  claim 17 , wherein the magnetic layer has a uniform third thickness as measured perpendicular to the ABS, the third thickness being greater than the respective first and second thicknesses. 
     
     
       19. The apparatus of  claim 15 , wherein the magnetic guard layer continuously extends along cross-track and longitudinal directions with respect to the write pole.